TOTAL - 40

🔹 20 basic (Objects + Arrays)

1. Sum values in object arrays

   • Input:

     { food: [10, 20, 30], travel: [5, 15], bills: [40, 60] }
     
     

   • Output:

     { food: 60, travel: 20, bills: 100 }
     
     

2. Count word occurrences in array

   • Input:

     ["apple", "banana", "apple", "orange", "banana", "apple"]
     
     

   • Output:

     { apple: 3, banana: 2, orange: 1 }
     
     

3. Swap keys and values of object

   • Input:

     { a: "x", b: "y", c: "z" }
     
     

   • Output:

     { x: "a", y: "b", z: "c" }
     
     

4. Find the largest value key

   • Input:

     { a: 10, b: 50, c: 20 }
     
     

   • Output:

     b
     
     

5. Flatten object of arrays into one array

   • Input:

     { fruits: ["apple", "banana"], veggies: ["carrot", "pea"] }
     
     

   • Output:

     ["apple", "banana", "carrot", "pea"]
     
     

6. Group people by city

   • Input:

     [
       { name: "A", city: "Delhi" },
       { name: "B", city: "Mumbai" },
       { name: "C", city: "Delhi" }
     ]
     
     

   • Output:

     { Delhi: ["A", "C"], Mumbai: ["B"] }
     
     

7. Filter object by values > 50

   • Input:

     { a: 20, b: 60, c: 40, d: 90 }
     
     

   • Output:

     { b: 60, d: 90 }
     

8. Find student with highest average mark

   • Input:

     { A: [80, 90], B: [70, 75, 85] }
     

   • Output:

     A
     

9. Unique values across all object arrays

   • Input:

     { x: [1,2,3], y: [2,3,4], z: [4,5] }
     
     

   • Output:

     [1,2,3,4,5]
     
     

10. Pick only given keys from object

    • Input:

      { name: "Rahul", age: 23, city: "Noida" }, ["name","city"]
      
      

    • Output:

      { name: "Rahul", city: "Noida" }
      
      

11. Find student with highest average marks

    • Input:

      { A: [80, 90], B: [70, 75, 85] }
      
      

    • Output:

      A
      
      

12. Sort object entries by values (ascending)

    • Input:

      { a: 3, b: 1, c: 2 }
      
      

    • Output:

      [["b",1], ["c",2], ["a",3]]
      
      

13. Count number of keys in object

    • Input:

      { a: 1, b: 2, c: 3 }
      
      

    • Output:

      3
      
      

14. Capitalize string values inside object

    • Input:

      { name: "alice", city: "delhi" }
      
      

    • Output:

      { name: "Alice", city: "Delhi" }
      
      

15. Convert object to query string

    • Input:

      { name: "Alice", age: 25 }
      
      

    • Output:

      "name=Alice&age=25"
      
      

16. Count even and odd numbers in array

    • Input:

      [1,2,3,4,5,6]
      
      

    • Output:

17. Find common keys between two objects

18. Convert array of objects to lookup by id